Topical fluoride treatment with fluoride solutions has been found quite effective in the prevention of dental caries. The most effective type of fluoride treatment is almost always conducted in a clinical environment because of the strong concentration of the fluoride solution that is applied to the teeth. Of course, clinical treatment of this nature severely limits access by the general public to this character of fluoride treatment. Accordingly, dentifrice preparations have been developed and marketed having low concentrations of various fluoride compounds and these preparations have gained widespread acceptance by the public. The anticaries effectiveness of dentifrice products has been materially enhanced by the development of anticaries agents, such as stannous fluoride, sodium monofluorophosphate sodium fluoride, etc. These anticaries agents, when incorporated in dentifrice products, provide topical fluoride treatment with daily dental hygiene. Tests have shown marked reduction in the occurrence of dental caries when the dentifrice utilized for daily dental hygiene includes a fluoride containing compound.
It is desirable to enhance the effectiveness of fluoride compounds, especially stannous fluoride, for caries prevention without necessitating an increase in the concentration of the fluoride compounds in dentifrice products that are available to the general public. For example, it has been found that a concentration of stannous fluoride in the range of 0.3%-0.5%, and preferably 0.4%, of a dentifrice composition yield good results from the standpoint of anticaries treatment. Increasing the concentration of fluoride compound in a dentifrice materially above the level of 0.4% may yield minimal increase in anticaries activity, but the risk of harmful concentrations becomes a matter for careful consideration. For that reason, it is desirable to maintain a concentration of a fluoride compound at about 0.4% of a dentifrice composition and to provide for an increase in the anticaries activity of the product by other suitable means.
The enamel of the teeth is defined by a crystalline latticework of hydroxy-apatite that is effectively resistant to absorption of most materials that are ordinarily present in the oral environment. Fluoride containing dentifrice materials are capable of penetrating the crystalline latticework to a limited degree and therefore fluoride treatment of the teeth is effective for caries resistance only under circumstances where the solution applied to the teeth includes a strong concentration of fluoride. For example, prophylactic pastes and gels utliized in dental offices contain fluoride at about 10% solution. The maximum allowable fluoride concentration in dentifrice materials sold to the public is about 0.4% solution and the fluoride effectiveness is therefore quite limited. It is desirable to provide a fluoride containing dentifrice material that is capable of accomplishing increased fluoride enhanced caries resistance without requiring concentration of fluoride in excess of 0.4% solution.
It is well known that fluoride penetrating the outer surface portion of the crystalline latticework of the enamel tends to leach out quite rapidly. The leaching action begins as soon as the oral cavity is rinsed after brushing, removing the fluoro chemical environment introduced by the dentifrice. It is desirable first to accomplish opening or activation of the crystalline latticework of the enamel and then to provide a surface sealing or capping effect for the enamel to retard the normal leaching action of the oral fluid which would otherwise allow rapid dissipation of the fluoride from the enamel. This activity will allow the fluoride to be retained deeply within the latticework as long as possible so as to provide long term anticaries activity even though fluoride is utilized at or below the weak solution range allowed by governmental authority.
Most dentifrice preparations have a pH in the neutral, slightly basic or slightly acid range. For example, known dentifrice materials having an acid pH do not exceed an acid pH of about 5. The primary reason for this is that decalcification begins to occur in the acid pH range and, since the enamel is eroded to some extent by the abrasive material during the brushing or scrubbing action of oral hygiene it is considered undesirable to cause further deterioration of the enamel by decalcification. It has been determined, however, that the enamel crystalline latticework begins to open or become active at an acid pH and tests indicate that crystalline latticework is able to accept deeper penetration of the fluoride as the latticework opens or becomes activated. Thus, it is desirable to accomplish opening or activation of the crystalline latticework by means of an acid pH to promote deep penetration of the fluoride into the crystalline latticework of the enamel without involving a pH significantly low that decalcification becomes a problem.
In some cases it will not be desirable to utilize a fluoride for daily anticaries activity. In this limited case it is desirable to provide a dentifrice composition that is capable of reacting with the enamel to develop caries resistance.
One of the important aspects of providing a dentifrice that has wide public acceptance is the appearance of the dentifrice material itself. Dentifrice material having a translucent, pleasantly colored appearance is, therefore, a desirable feature insofar as the material also provides optimum prevention of caries and is pleasing to the taste.
Accordingly, it is a primary feature of the present invention to provide a novel dentifrice material that incorporates a fluoride compound for fluoride induced anticaries treatment of the teeth and further incorporates an acid phosphate compound that functions to enhance the anticaries prevention capability of the fluoride compound, without increasing the concentration of the fluoride compound in the dentifrice composition beyond the level of concentration allowed by governmental authority.
It is also a feature of this invention to provide a novel dentifrice composition that incorporates a sufficient quantity of sodium dihydrogen phosphate to alter the crystalline latticework of the enamel causing material enhancement of the resistance of tooth enamel to the development of dental caries.
It is a further feature of this invention to provide a novel dentifrice material which incorporates a sufficient quantity of sodium dihydrogen phosphate to alter the crystalline latticework of the enamel to render the enamel actively receptive to deep penetration of fluoride ions into the crystalline latticework.
Among the several features of the invention is noted the contemplation of a novel dentifrice composition having an acid pH range within which deep penetration of fluoride ions is induced and a subsequent stannous capping effect is developed that effectively prevents leaching of the fluoride or phosphate ions from the enamel of the teeth.
It is also a feature of this invention to provide a novel dentifrice composition incorporating sodium dihydrogen phosphate which reacts with the enamel structure of the teeth to develop an electrically stable fluorophosphate complex within the enamel that promotes long term stability of the caries inhibiting effect of stannous fluoride incorporated therewith.
It is also a feature of the present invention to provide a novel dentifrice material that incorporates stannous fluoride as the fluoride compound, with sodium dihydrogen phosphate as the acid phosphate compound, the resulting combination of the stannous fluoride and acid phosphate causing enhanced fluoride treatment effectiveness of the stannous fluoride.
It is another feature of this invention to provide a novel dentifrice material incorporating a fluoride compound and an acid phosphate compound in a water free gel carrier in order to prevent degradation of the fluoride compound.
It is an even further feature of the present invention to provide a novel dentifrice composition wherein stannous fluoride and sodium dihydrogen phosphate are combined in substantially equal proportions by volume and, at which proportional combination, provide a dentifrice wherein the anticaries effectiveness of the fluoride and the phosphate compounds are materially enhanced.
Another feature of this invention concerns the provision of a novel sodium dihydrogen phosphate containing dentifrice wherein the pH of the resulting dentifrice is in the range of between 2 and 5 and preferably about 3.5.
It is also a feature of this invention to provide a novel fluoride containing dentifrice material that is of pleasing appearance in that it is in the form of a pleasingly colored translucent gel.
It is also a feature of this invention to provide a dentifrice composition incorporating sodium dihydrogen phosphate in sufficient amount to alter the crystalline structure of the enemel and rendering such enamel resistant to caries.
Another feature of this invention concerns the provision of stannous fluoride containing dentifrice material that may be provided with a water-free gel carrier for effective use in single tube delivery systems, or, as an alternative, may be provided in a water containing carrier when double tube delivery systems are to be employed.
Other and further objects, features and advantages of this invention will become obvious to one skilled in the art upon an understanding of the illustrative embodiments about to be described, and various advantages, not referred to herein, will occur to one skilled in the art upon employment of the invention in practice.